feedback7 R22-RENDER: a unit killed on the step of its push lies where the sim put it — a dying view's sample anchors the slide too (Grok's review of fb7-render, HIGH); golden: unchanged

A push and a kill on the same sim step bring the displace fx and the 'die' together: the view died before its slide
could anchor, and render/app.js syncBattle gives a dying view only its position (v.x = s.x) — never sync(), the only
place that set slide.live — so update() held the slide's start until its 0.5 s timeout, past the 0.8 s DIE window,
and dropped it: the body stayed on its pre-push tile (8.852 instead of the sim's 10.5; a summoned enemy and a flyer
alike). The per-view step of syncBattle is now units.js syncView (unchanged for living, device and revived views); its
dying branch calls UnitView.followSample, the position part of sync(): the sample anchors a slide from `at` on, and is
the position only when no slide owns it. A slide whose destination snapshot never shows (the unit left the snapshots)
now goes on to the fx's destination after the 0.5 s hold instead of being dropped where it started.

The frame-order test fed the view with sync() after its death and stepped the battle through the harness (whose
step() drained the events away from the test's own queue): it now steps the battle itself and goes through syncView.

Tests: test/render/unitview.test.js 38/38 — the app.js frame order over real battles: a 1.7-tile push; a kill on the
push's step for a route enemy, a summoned one and a flyer (the three failed before: bodies at 8.852 / 7.262 / 8.852)
and a kill 6 ticks later — the body ends where the sim's lies, every frame step < 0.35 tiles, no step back for the
same-step kills; a never-shown slide goes to the destination. Render interp, attack recovery, champagne, eyemask,
enemy attack clips, sim displace-fx: 94/94 with unitview.

public/js/render/app.js

@@ -117,7 +117,7 @@ import { fxForm } from '../../../shared/protocol.js';
 import { Camera, presetCamera, lerpCamera, easeInOutCubic, pickTile, normRect } from './projection.js';
 import { SnapshotBuffer, frameTime } from './interp.js';
 import { TileField } from './tiles.js';
-import { UnitView, ItemView, DeviceView, FORMS } from './units.js';
+import { UnitView, ItemView, DeviceView, FORMS, syncView } from './units.js';
 import { FxSystem, ensureDamageFonts } from './fx.js';
 import { createDragController, pieceTile } from './drag.js';
 import { backdropTextures, shadowTexture, refreshTierChips, silhouetteTexture } from './textures.js';
@@ -1500,9 +1500,7 @@ export async function createFieldView(host, options = {}) {
       if (!v) v = battleView(id) || createUnknown(id, s);
       if (!v) continue;
       if (!v._seen) { v._seen = true; v.fadeIn = 0; }
-      if (v.alive || v.info?.kind === 'device') v.sync(s, renderT);
-      else if (v.dying > 0) { v.x = s.x; v.y = s.y; }
-      else if (s.anim !== ANIM.DIE && s.hp > 0) { v.revive?.(); v.sync(s, renderT); }
+      syncView(v, s, renderT);
     }
     // knocked-out operators waiting to redeploy (b.snap `down`, user playtest #4 item 9): their view stays on the
     // field knocked down under a redeploy ring (UnitView.setDown) — made on the spot for one already down when this